US 89 is functionally classified as a Rural Principal Arterial route and designated as part of the National Highway System (NHS).  The primary function of this route is the safe and efficient movement of people and goods over long distances while allowing for limited access to adjacent lands.  As part of the National Highway System, US 89 is considered a strategic national highway that is critical to national security and economic viability.  This highway also provides visitors a route to the Jackson Hole region and two major national parks.

Purpose and need for improvements

The purpose of this project is to improve U.S. 89 between Thayne and Etna to fulfill its intended function as a Rural Principal Arterial Route.

The project is needed to:

  • Increase highway capacity and improve mobility.
  • Improve highway safety.

Capacity and mobility

  • Annual Average Daily Traffic (AADT) is expected to increase from 4,672 in 2015 to 7,296 in 2040 (56% increase).
  • Percent time spent following slower vehicles is expected to increase to 79% by 2040.
  • Level of Service (LOS) is currently D; expected to approach E by 2040. 
  • Level of Service is a measure of traffic congestion based on average travel speed, time spent following a slower vehicle, and the volume of vehicles using the highway vs. the volume it was designed to handle; assigns performance grades from A (excellent) to F (extremely poor)

Improve Safety

With 162 access points and growing volatile mixes of traffic there is a concern for an increase in potential crashes.

What is a Rural Principal Arterial route?

It provides the safe and efficient movement of people and goods over long distances while allowing for limited access to adjacent lands.

It typically has high mobility and high access control, with a limited number of access points.